A key information management device includes: a key information distribution unit configured to distribute key information to a company that provides a delivery service that allows an inside of a vehicle, a building, or a facility used by a user to be designated as a delivery destination of a package, key information being used by a delivery person of the company to unlock a specified entrance of the vehicle, the building, or the facility; and a determination unit configured to determine whether or not the delivery person who delivers the package has reached within a specified range of the vehicle, the building, or the facility, wherein the key information distribution unit is configured to distribute the key information to the company when the determination unit determines that the delivery person has reached within the specified range of the vehicle, the building, or the facility.